From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: vhost, kcov: collect coverage from vhost_worker Add kcov_remote_start()/kcov_remote_stop() annotations to the vhost_worker() function, which is responsible for processing vhost works. Since vhost_worker() threads are spawned per vhost device instance the common kcov handle is used for kcov_remote_start()/stop() annotations (see Documentation/dev-tools/kcov.rst for details). As the result kcov can now be used to collect coverage from vhost worker threads. Link: http://lkml.kernel.org/r/e49d5d154e5da6c9ada521d2b7ce10a49ce9f98b.1572366574.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Anders Roxell <anders.roxell@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: David Windsor <dwindsor@xxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Elena Reshetova <elena.reshetova@xxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Jason Wang <jasowang@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/vhost/vhost.c | 6 ++++++ drivers/vhost/vhost.h | 1 + 2 files changed, 7 insertions(+) --- a/drivers/vhost/vhost.c~vhost-kcov-collect-coverage-from-vhost_worker +++ a/drivers/vhost/vhost.c @@ -30,6 +30,7 @@ #include <linux/sched/signal.h> #include <linux/interval_tree_generic.h> #include <linux/nospec.h> +#include <linux/kcov.h> #include "vhost.h" @@ -357,7 +358,9 @@ static int vhost_worker(void *data) llist_for_each_entry_safe(work, work_next, node, node) { clear_bit(VHOST_WORK_QUEUED, &work->flags); __set_current_state(TASK_RUNNING); + kcov_remote_start_common(dev->kcov_handle); work->fn(work); + kcov_remote_stop(); if (need_resched()) schedule(); } @@ -546,6 +549,7 @@ long vhost_dev_set_owner(struct vhost_de /* No owner, become one */ dev->mm = get_task_mm(current); + dev->kcov_handle = kcov_common_handle(); worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); if (IS_ERR(worker)) { err = PTR_ERR(worker); @@ -571,6 +575,7 @@ err_worker: if (dev->mm) mmput(dev->mm); dev->mm = NULL; + dev->kcov_handle = 0; err_mm: return err; } @@ -682,6 +687,7 @@ void vhost_dev_cleanup(struct vhost_dev if (dev->worker) { kthread_stop(dev->worker); dev->worker = NULL; + dev->kcov_handle = 0; } if (dev->mm) mmput(dev->mm); --- a/drivers/vhost/vhost.h~vhost-kcov-collect-coverage-from-vhost_worker +++ a/drivers/vhost/vhost.h @@ -173,6 +173,7 @@ struct vhost_dev { int iov_limit; int weight; int byte_weight; + u64 kcov_handle; }; bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len); _
